Effect of low frequency magnetic fields on the growth of MNP-treated HT29 colon cancer cells.

Recent investigations have attempted to understand and exploit the impact of magnetic field-actuated internalized magnetic nanoparticles (MNPs) on the proliferation rate of cancer cells. Due to the complexity of the parameters governing magnetic field-exposure though, individual studies to date have raised contradictory results. In our approach we performed a comparative analysis of key parameters related to the cell exposure of cancer cells to magnetic field-actuated MNPs, and to the magnetic field, in order to better understand the factors affecting cellular responses to magnetic field-stimulated MNPs. We used magnetite MNPs with a hydrodynamic diameter of 100 nm and studied the proliferation rate of MNPs-treated versus untreated HT29 human colon cancer cells, exposed to either static or alternating low frequency magnetic fields with varying intensity (40-200 mT), frequency (0-8 Hz) and field gradient. All three parameters, field intensity, frequency, and field gradient affected the growth rate of cells, with or without internalized MNPs, as compared to control MNPs-untreated and magnetic field-untreated cells. We observed that the growth inhibitory effects induced by static and rotating magnetic fields were enhanced by pre-treating the cells with MNPs, while the growth promoting effects observed in alternating field-treated cells were weakened by MNPs. Compared to static, rotating magnetic fields of the same intensity induced a similar extend of cell growth inhibition, while alternating fields of varying intensity (70 or 100 mT) and frequency (0, 4 or 8 Hz) induced cell proliferation in a frequency-dependent manner. These results, highlighting the diverse effects of mode, intensity, and frequency of the magnetic field on cell growth, indicate that consistent and reproducible results can be achieved by controlling the complexity of the exposure of biological samples to MNPs and external magnetic fields, through monitoring crucial experimental parameters. We demonstrate that further research focusing on the accurate manipulation of the aforementioned magnetic field exposure parameters could lead to the development of successful non-invasive therapeutic anticancer approaches.

Arrangement at the nanoscale: Effect on magnetic particle hyperthermia.

In this work, we present the arrangement of Fe3O4 magnetic nanoparticles into 3D linear chains and its effect on magnetic particle hyperthermia efficiency. The alignment has been performed under a 40 mT magnetic field in an agarose gel matrix. Two different sizes of magnetite nanoparticles, 10 and 40 nm, have been examined, exhibiting room temperature superparamagnetic and ferromagnetic behavior, in terms of DC magnetic field, respectively. The chain formation is experimentally visualized by scanning electron microscopy images. A molecular Dynamics anisotropic diffusion model that outlines the role of intrinsic particle properties and inter-particle distances on dipolar interactions has been used to simulate the chain formation process. The anisotropic character of the aligned samples is also reflected to ferromagnetic resonance and static magnetometry measurements. Compared to the non-aligned samples, magnetically aligned ones present enhanced heating efficiency increasing specific loss power value by a factor of two. Dipolar interactions are responsible for the chain formation of controllable density and thickness inducing shape anisotropy, which in turn enhances magnetic particle hyperthermia efficiency.

Reducing the inversion degree of MnFe2O4 nanoparticles through synthesis to enhance magnetization: evaluation of their (1)H NMR relaxation and heating efficiency.

Manganese ferrite (MnFe2O4) nanoparticles of identical size (9 nm) and with different inversion degrees were synthesized under solvothermal conditions as a candidate theranostic system. In this facile approach, a long-chain amine, oleylamine, was utilized as a reducing and surface-functionalizing agent. The synthesized nanoparticles were shown to have a cubic-spinel structure as characterized by TEM and XRD patterns. Control over their inversion degree was achieved by a simple change of manganese precursor from Mn(acac)2 to Mn(acac)3. The variation in the inversion degree is ascribed to the partial oxidation of Mn(2+) to Mn(3+), as was evidenced by X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy at both the Fe and Mn K-edges. The reduction of the inversion degree from 0.42 to 0.22 is close to the corresponding bulk value of 0.20 and led to elevated magnetization (65.7 emu g(-1)), in contrast to the Néel temperature, which was decreased owing to the weaker superexchange interactions between the tetrahedral and octahedral sites within the spinel structure. In order to evaluate the performance of these nanoprobes as a possible bifunctional targeting system, the (1)H NMR relaxation of the samples was tested together with their specific loss power under an alternating magnetic field as a function of concentration. The hydrophobic as prepared MnFe2O4 nanoparticles converted to hydrophilic nanoparticles with cetyltrimethylammonium bromide (CTAB). The MnFe2O4 nanoparticles, well-dispersed in aqueous media, were shown to have r2 relaxivity of up to 345.5 mM(-1) s(-1) and heat release of up to 286 W g(-1), demonstrating their potential use for bioapplications.

The effect of composition and structural ordering on the magnetism of FePt nanoparticles.

Spherical 4 nm FePt nanoparticles were synthesized by the simultaneous decomposition of Fe(CO)5 and the polyol reduction of Pt(acac)2. The final Fe-to-Pt composition was tuned between 15-55 at.% by varying the ingredient precursor ratios. The effect of composition and structural ordering on the macroscopic magnetic features of final FePt nanoparticles was examined via post-synthetic annealing stages at different conditions. Structural ordering is promoted in all cases, though samples approximating equiatomic Fe/Pt ratios eventually transform to fct-FePt phase while the FePt3-phase is favored for the Pt-richer samples. Consequently, the magnetic features of the annealed nanoparticles may be categorized; the hard magnetic FePt region dominating for Fe content between 40-55 at.% and the soft magnetic FePt3 region dominating in the region 20-30 at.% while Fe content less than 20 at.% results in Pt-richer phases with diminishing ferromagnetic behavior.

Tuning the perpendicular magnetic anisotropy of co-based layers in multilayered systems.

The combination of Pt with Co either in alloy or in multilayer form is widely studied among the potential magnetic media for ultrahigh density magnetic recording. On the other hand the combination of Co with Cr in alloy form is currently providing commercial magnetic media. In an effort to further exploit and benefit from both systems, we fabricated Co(1-x)Cr(x)/Pt multilayers with two adjustable parameters. The first one is the Cr concentration on CoCr layer (x = 0, 5, 30), which modulates segregation effects on Co grains, thus tunes macroscopic magnetic features such as saturation magnetization and coercive field. The second one is the small layer thickness (< or = 0.6 nm) that affects interlayer coupling, perpendicular magnetic anisotropy and magnetization enhancement through spin polarization of Pt atoms in a ferromagnetic environment. The X-ray diffraction patterns verified the existence of multilayered structures following a preferable face-centered-cubic stacking. The Pt thickness and Cr concentration are found to significantly affect the macroscopic magnetic behavior. It is remarkable the fact that, samples present perpendicular anisotropy that scales with Pt thickness and temperature, even in the case of significant Cr concentration (30% in the alloy) when ferromagnetic behavior is expected to diminish according to relevant studies in alloys and in bulk films. Such an effect may be attributed to spin-polarization of Pt interlayers and was evidenced by X-ray magnetic circular dichroism. The spin-polarization of Pt is also the drive for the strong magneto-optic enhancement in the ultra-violet region between 4.5 and 5 eV shown by magnetooptic Kerr spectroscopy.

Size-induced effects in wet-chemically synthesized CoPt3 nanoparticles.

CoPt3 alloy spherical nanoparticles with sizes tuned between 3-7 nm were produced by the simultaneous thermal treatment of proper platinum and cobalt precursors in the presence of surfactants. The final size and composition of the particles are determined by the precursors' ratio, the chemical behavior of Co precursors and the stabilizing efficiency of the surfactants. By employing higher reaction temperatures (approximately 350 degrees C) better alloying is achieved leading to enhancement of macroscopic magnetic features and decrease of the superparamagnetic limit down to 7 nm.

Using magnetic circular dichroism for the study of the magnetization and the magnetic moments of atoms in Nd(3)Fe(27.5)Ti(1.5).

An element-specific study of the Nd(3)Fe(27.5)Ti(1.5) compound using the hard x-ray magnetic circular dichroism (XMCD) technique is presented. The Nd L(2) and L(3) edge XMCD, as well as the Fe K edge XMCD, were measured in a magnetically oriented sample, parallel and perpendicular to its alignment direction. The XMCD spectra were recorded at three different temperatures, above, below and in between the characteristic peaks that the specific compound presents in AC susceptibility measurements. By probing the Nd L edges and the Fe K edge XMCD, we found that the dipolar R(5d)-Fe(3d) exchange interaction behaves differently with temperature change than the Fe-Fe magnetic interaction. Those differences appear to be in the vicinity of the AC susceptibility characteristic peaks. An XMCD signal was recorded at the Ti K edge, revealing a small orbital polarization due to the hybridization with Fe atomic states. This demonstrates the existence of a small finite magnetic moment in Ti atoms.

Matting of hair: what is the role of conditioners?

Matting of the hair is a very rare and multifactorial condition affecting usually women. We present three female patients with matting of the hair as a result of the shampoo used. In all three cases, cutting of the affected hair was unavoidable.

'Dalmatian dog'-like skin eruption (two cases of multifocal fixed drug eruption induced by mefenamic acid).

Mefenamic acid is a common widely prescribed drug with analgesic activity. Authors report two cases of multifocal fixed drug eruption induced by mefenamic acid. Cases were diagnosed on basis of clinical examination and histopathology of skin lesion. Only a few cases have been reported in the literature and these are the first two described in Greece.

Histological changes induced by tibolone and estrogen/glucocorticoid on aging skin.

OBJECTIVE: The aim of this study was to investigate the oral effects of tibolone and mestranol plus paramethasone on the skin of postmenopausal women. A second purpose was to determine endometrial thickness with transvaginal ultrasound. MATERIALS AND METHODS: This randomized study was carried out in 39 healthy postmenopausal women. Skin biopsies were obtained from the thigh area by a single punch, before and after treatment, and the sections were evaluated. Current characteristics of both groups were measured at follow-up. RESULTS: No gross differences were observed in size, distribution or imaging of collagen, elastic or reticular fibers. Statistically significant changes were found in the papillar dermis thickness. There were no statistically significant differences in the sonographic measurements. CONCLUSION: The estrogen/glucocorticoid combination provides a way to evaluate in parallel the cellular metabolism effects on the irreversible aging process. The current results encourage widening these observations of the possible advantage of this combination, in order to alleviate the cellular degenerative process.

Transdermal estrogen with a levonorgestrel-releasing intrauterine device for climacteric complaints versus estradiol-releasing vaginal ring with a vaginal progesterone suppository: clinical and endometrial responses.

OBJECTIVE: Our purpose was to compare the effects of a new estradiol-releasing vaginal ring with progesterone given as a vaginal suppository, versus the efficacy, safety and acceptability of an intrauterine device releasing levonorgestrel combined with estradiol, delivered transdermally from a patch. Climacteric symptoms, bleeding pattern and endometrial histologic features were studied. METHODS: Fifty six parous, postmenopausal women with urogenital symptoms were allocated in two groups for one year: 28 women receiving estradiol by a vaginal ring and a 100 mg vaginal progesterone suppository 7 days every month and 28 women receiving a continuous transdermal daily dose of 50 micrograms of estradiol with a levonorgestrel-releasing intrauterine device inserted. All the patients were subjected to vaginosonographic examination followed by thorough pathological examination of the uterine curetting samples. RESULTS: A mean endometrial thickness (double layer) of 2.9 and 3.0 mm, respectively, was found to be predictive of normal endometrium. Both treatment regiments effectively relieved climacteric symptoms. Endometrial proliferation was not observed. Spotting was more common in the intrauterine device group than in the vaginal ring group. CONCLUSIONS: Treatment of urogenital symptoms in postmenopausal women with these two forms of hormone replacement therapy is shown to be an effective and safe method, exhibiting advantages over other methods of treatment.

Predictive factors used to justify hysterectomy after loop conization: increasing age and severity of disease.

OBJECTIVE: To determine the interpretability and significance of the traditional factors used to predict residual dysplasia in hysterectomy specimens after loop conization. MATERIALS AND METHODS: Loop electrosurgical cervical conization was performed on 372 patients. Ninety three women had a hysterectomy within 6 months of the loop conization. Residual disease was defined as cervical intraepithelial neoplasia or cancer in the hysterectomy specimen. RESULTS: Of the 93 patients having a subsequent hysterectomy, 36 (38.7%) has residual disease in their hysterectomy specimen. The mean age of the patients with residual disease in the post loop conization hysterectomy specimen was 42.22. The mean age of those free of residual disease was 29.42. By multivariate analysis, dysplasia involving the ectocervical margin (p = 0.34) and the endocervical margin (p = 0.35) was not predictive of disease in the hysterectomy specimens. Endocervical curettage (p = 0.005), glandular involvement (p = 0.01), loop conization pathology findings (p < 0.05) and cytological examination (p < 0.001) were predictive of residual dysplasia. CONCLUSIONS: Cytological reports, increasing age, severity of disease, gland involvement and endocervical curettage were the only factors that accurately predicted residual dysplasia. The presence or absence of dysplasia in the loop conization, ectocervical margin and endocervical margin was not predictive of residual dysplasia in post loop conization hysterectomy specimens.

A comparative study of the effects of an estradiol-releasing vaginal ring combined with an oral gestagen versus transdermal estrogen combined with a levonorgestrel-releasing IUD: clinical findings and endometrial response.

OBJECTIVE: Our purpose was to compare the effects of a new estradiol-releasing vaginal ring with an oral progestin versus the efficacy, safety and acceptability of an intrauterine device releasing levonorgestrel combined with estradiol, delivered transdermally from a patch. Climacteric symptoms, bleeding pattern, and endometrial histologic features were studied. MATERIALS AND METHODS: Fifty-six parous, postmenopausal women with urogenital symptoms were allocated to two groups for 1 year" 28 women receiving estradiol by a vaginal ring (2 mg/3 months) and an oral progestin for 7 days every month and 28 women receiving a continuous transdermal daily dose of 50 micrograms of estradiol with a levonorgestrel-releasing (20 micrograms/day) intrauterine device inserted. All the patients were subjected to vaginosonographic examination followed by thorough pathological examination of uterine curetting samples. RESULTS: A mean endometrial thickness (double layer) of 2.9 and 3.0 mm, respectively, was found to be predictive of normal endometrium. Both treatment regimens effectively relieved urogenital symptoms. Endometrial proliferation was not observed. CONCLUSIONS: Treatment of urogenital symptoms in postmenopausal women with these two forms of hormone replacement therapy was shown to be an effective and safe method, exhibiting possible advantages over other methods of treatment.

PIP: At the outpatient obstetric-gynecologic clinic of Areteion Hospital in Athens, Greece, 56 postmenopausal women, 48-76 years old and with signs and symptoms of estrogen deficiency-induced atrophic vaginitis, were randomly assigned to either the group using a silicon vaginal ring containing 2 mg micronized 17-beta- estradiol and oral medroxyprogesterone acetate for 7 days at the beginning of each month (group A) or the group using a combination of 50 mcg estradiol via a transdermal patch and a levonorgestrel-releasing IUD (group B). The women were using these regimens for 12 months. The purpose of the study was to compare the clinical and endometrial effects of the new vaginal ring with an oral progestin with those of the established hormone replacement regimen of transdermal estrogen and a levonorgestrel-releasing IUD. Vaginal ultrasound and pathologic examination of uterine curettage samples were used to determine endometrial effects. The urogenital complaints of all 56 women disappeared. The mean endometrial thickness before treatment was similar for both groups (2.9 mm for group A and 3 mm for group B) and was not significantly different than endometrial thickness after treatment (2.6 and 2.8 mm, respectively). Endometrial proliferation was not observed. The mean endometrial thickness at baseline predicted normal endometrium. After 3 months of treatment, vaginal bleeding patterns were similar in both groups. These findings confirm that both regimens effectively treat estrogen deficiency-induced urogenital disorders and do not increase the risk of endometrial proliferation.

Comparison of surgical and postoperative complications of vaginal hysterectomy and Manchester procedure.

OBJECTIVE: The Manchester procedure (MP) was compared to vaginal hysterectomy (VH). Surgical and postoperative complications were evaluated. MATERIAL AND METHODS: A retrospective review of women undergoing VH and MP for uterine prolapse was performed. All the operations were performed between 1974-1994. MP was performed in 190 patients and VH (Heaney technique) in 231 women. RESULTS: MP patients, when compared to VH patients, were more likely to be older and postmenopausal at the time of surgery. Statistically significant differences were found for operative time and blood loss. This difference was not dependent on the performance of anterior or posterior repair. CONCLUSIONS: We suggest the use of MP as an alternative to VH in the absence of uterine pathology in appropriate candidates with uterine prolapse.

Power Doppler ultrasound: a potentially useful alternative in diagnosing pelvic pathologic conditions.

INTRODUCTION: To evaluate the efficacy of power Doppler sonography in depicting soft-tissue hyperemia in endometriosis and other pelvic inflammatory conditions thirty-one patients with predominantly pelvic inflammatory symptoms were evaluated. MATERIALS AND METHODS: Power Doppler sonography at 5 MHz and a pulse repetition frequency of 800 Hz was used. All the women underwent laparoscopy after 10 days. RESULTS: Soft-tissue hyperemia was seen on power Doppler sonograms in 22 of the symptomatic patients. In these women Doppler demonstrated a diffused "blush" of almost or the entire symptomatic sites. Specificity was 52.4%, sensitivity 47.1% and the positive predictive value was 53.2%. CONCLUSION: Power Doppler sonography showed hyperperfusion in many cases associated with pelvic inflammatory pathology. It is a potentially useful adjunct to standard color Doppler imaging in depiction of vascular flow.